Joint CFO, data symbol and channel response estimation in OFDM systems

A joint iterative estimator is developed that estimates both the carrier frequency offset (CFO) and data sequence for orthogonal frequency-division multiplexing systems. For frequency-selective fading channels, the estimator also incorporates channel response estimation. The estimator operates in the frequency domain, after the Fourier transformation. Convergence analysis shows that the CFO estimator converges to the actual value in the almost sure sense if the initial CFO is less than approximately one half of the subcarrier spacing. The complexity of the proposed algorithm can be made manageable by using proper windowing prior to the Fourier transformation and decision feedback techniques. A simulation study is also conducted to show the bit error rate as well as the mean squared error performances of the proposed algorithms.